Intelligent Well Control System for Three or More Zones

ABSTRACT

An intelligent well system can service three or more zones that have gravel packed screens. A modular system features a screen and a surface controlled production valve on an internal blank pipe that internally straddles the screen. A gravel exit valve is disposed above the blank pipe and the blank pipe can optionally have a fluid loss control valve. A gravel pack/fracturing assembly can engage each module and close the fluid loss valve and gravel outlet valve on the way out of a module. Optionally the fluid loss valve can be eliminated if the gravel packing and fracturing string has the ability to power the production valve. The modules can be connected by wet connects as can the production string to make the intelligent well system functional from the surface.

FIELD OF THE INVENTION

The field of this invention is intelligent well control from the surfacewithout intervention and more specifically in the context of sandcontrol completions in multiple zones and more specifically targetingthree or more zones.

BACKGROUND OF THE INVENTION

Intelligent well control generally involves a way to control and monitorwell conditions from the surface without having to intervene in thewellbore. Many applications of such systems have been employed and oneis illustrated in FIG. 1. FIG. 1 shows an open hole 10 with packers 12,14 and 16 isolating zones 18, 20 and 22 respectively with a valve 24, 26and 28 respectively in each zone. A production packer 30 is disposed inliner 32 with production tubing 34 extending to the surface. Liner 32 ishung to well casing (not shown) at hanger 36. A valve 38 gives access toa fourth zone 40 between packers 30 and 16. Lines 42 which can behydraulic or electric or fiber optic extend from the surface through thehanger 36 and the packers 12, 14, 16 and 30 to reach the valves 24, 26,28 and 38 as well as sensors, shown as PDHMS (Permanent DownholeMonitoring System), to determine well conditions such as pressure ortemperature. One or more of the zones 18, 20, 22 or 40 can be surfaceselected for production and the flowing conditions monitored from thesurface. If a zone produces water for example it can be cut off from thesurface. Other well parameters can be monitored and communication ofinformation can take place in either direction from the producing zonesto the surface.

The intelligent well concept has been adapted to gravel pack screencompletions as shown in FIG. 2. There a completion assembly 44 includespackers 46, 48 and 50 which define two zones 52 and 54. Screens 56 and58 align respectively with zones 52 and 54 and are part of thecompletion assembly 44. The objective of this two zone arrangement is tobe able to independently produce the discrete zones. In order to do thisa production string 60 is run in and its production packer 62 is set.Valves 64 and 66 are in the string 60 below the packer 62. Valve 66 isencased in a shroud 68 which has a tail section that engages seals 70and 72 so that flow to valve 66 can only come through screen 56 whilethe tailpipe in effect seals off an annular space 74 inside screen 58.As indicated by arrow 76, the annular space 74 is in fluid communicationwith valve 64 to allow discrete access from zone 54 into the string 60.Arrow 78 shows the flow access to valve 66 from zone 52. As part of thisintelligent completion, control lines such as those that carrypressurized fluid are run in pairs to opposing sides of an operatingpiston that in turn moves the valves 64 and 66 to the desired positionfrom the surface without any well intervention. FIG. 3 shows pistoncylinders 80 and 82 each respectively having a piston 84 and 86 insideand each responsive to pressure in one of two control lines connected tothe respective cylinder. Some of the valves are omitted for clarity butit is clear to those skilled in the art that pressure can be applied toline 88 and if no pressure is applied to lines 90 and 92 at the sametime that both pistons 84 and 86 and the respective valves 64 and 66will be moved to the same position. By applying pressure to both line 88and one of lines 90 or 92 the valves 64 and 66 will assume oppositepositions. A range of positions between open and closed for each valve64 and 66 is possible at any given time.

While the above layout has worked in the past for two zones, the problemoccurs if more than two zones are involved and it is made that much moredifficult to have the available space if the completion assembly 44 hasa smaller diameter. The problem is a lack of space for nesting enoughshrouds that are concentrically disposed. For example, a three zonevariation of FIG. 2 would require a second shroud within shroud 68 toisolate another valve (not shown) that would be located below valve 66and service another zone further downhole past zone 52. There is simplyno room in such wells with the FIG. 2 configuration to add additionalzones to a completion with gravel packed screens. Another problem is thespace-out of multiple seal assemblies with multiple concentric stringswhile landing the completion.

The method and associated apparatus of the present invention solves thisproblem. It provides a modular design that allows modules to be stackedin different zones. The modules carry a screen and an internal blankpipe that has the surface operated valve and a gravel exit port. A fluidloss valve can also be provided. A known gravel packing assembly using acrossover and a wash pipe with a sleeve shifter can be employed togravel pack or fracture in the known manner. The wash pipe when raisedto the next zone will close a fluid loss valve in a module and thegravel exit port. Lines can extend between modules and wet connectswhich are quick couplers connected to each other can be used to operablyconnect the valves to be operated from the surface from the modules andup to the surface on the outside of the production string. Wet connectsare illustrated in U.S. Pat. Nos. 7,228,898; 7,165,892; 6,776,636;6,755,253; 6,439,932; and 5,294,923. Optionally the gravel packing andfracturing running tool can be equipped with various control lines thattag into a module so that real time conditions during the gravel packingand fracturing can be monitored at the surface. With the use of such adevice the production valves that will later be controlled from thesurface can also be used for double duty as fluid loss control valves.The screen can have fiber optic inside of it that the running tool cantag into so that strain on the screen can be measured during graveldeposition to gauge the effectiveness of gravel distribution outside thescreen. The modules would not need a nesting feature, to eliminate thespace problem. Control of a given module can shift from a running toolthat engages the module to a surface control from a production stringfrom the surface after the running tool is removed such as when thevarious zones are fractured and the associated strings are gravelpacked.

These and other features of the present invention will be more apparentto those skilled in the art from a review of the detailed description ofthe preferred embodiment below and the associated drawings, whilerecognizing that the full scope of the invention is given by the claimsthat are attached below.

SUMMARY OF THE INVENTION

An intelligent well system can service three or more zones that havegravel packed screens. A modular system features a screen and a surfacecontrolled production valve on an internal blank pipe that internallystraddles the screen. A gravel exit valve is disposed above the blankpipe and the blank pipe can optionally have a fluid loss control valve.A gravel pack/fracturing assembly can engage each module and close thefluid loss valve and gravel outlet valve on the way out of a module.Optionally the fluid loss valve can be eliminated if the gravel packingand fracturing string has the ability to power the production valve. Themodules can be connected by wet connects as can the production string tomake the intelligent well system functional from the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prior art 4 zone open hole intelligent well completionsystem with no screens;

FIG. 2 is a prior art two zone intelligent well completion system withdrop in production valves and a shroud to isolate the two zones;

FIG. 3 is a detailed view of the hydraulic system that is surfaceoperated to move the two valves shown in FIG. 2;

FIG. 4 is an illustration of a single stackable module that can be thelower module of an assembly that can do multiple zones in an intelligentwell system;

FIG. 5 is a detailed sectional elevation view of the module shown inFIG. 4 that can be elsewhere in a stack of modules and showing therouting of lines through the module.

FIG. 6 is an alternative embodiment to FIG. 5 showing the connectionswith an axial orientation for connection in the wet connection locatednear at least one end.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One module 100 in a screened completion string is illustrated in FIG. 4.The modules 100 can be connected directly to each other across a longproducing interval or they can have blank pipe for proper spacing inmultiple zones downhole. Each module 100 has at least one screen section102 and an internal blank pipe 104 that spans the screen 102 and issealed on opposed ends 106 and 108. There is a gravel exit port with asliding sleeve to selectively open and close the port 110. The port 110is offset from the blank pipe 104. A production valve 112 is in blankpipe 104 and the module is pre-piped with control lines 114 better seenin FIG. 5. The hydraulic control lines 114 extend from an upper end 116to a lower end 118. In one alternative, the radial exit at lower end 118is between seals 120 and 122. Similarly at opposite end 116 there is aradial exit for the hydraulic lines between seals 124 and 126 of anadjacent blank pipe or other module 128 whose lower end is only shown atthe top of FIG. 5. Alternatively, the line pairs such as 119 and 121 canline up axially when mated together as shown in FIG. 6. Other lines forpower or signal or information such as fiber optic are schematicallyrepresented as 130 and extend from an upper end 132 to a lower end 134.A seal 136 is on the other side of the end of such lines from seal 120at end 134. At the opposite end 132 the next module or blank pipe 128has seals 124 and 138 which straddle end 132 to make a sealingconnection. Not shown at either end for clarity of the drawing butpresent is a rotational orientation device so that the connection atopposed ends is properly aligned to provide continuity of pressurizedlines, electrical lines or fiber optic lines. Devices that align andconnect in a sealing manner a variety of lines in a wet downholeenvironment are known in the art as wet connects with one 140 beingschematically illustrated at the top of FIG. 4 in conjunction with apacker 142 having a seal 144 and slips 146.

Finally, there is an optional fluid loss valve 148 which is typically asliding sleeve type that can be operated by a wash pipe of a knowngravel packing assembly which on the way out of a zone after gravelpacking it through the open valve 110 and taking fluid returns throughthe screen 102 through valve 148 during the gravel pack, will close bothvalves on the way out of the zone. This closes the screen 102 until thatzone is ready to be produced and closes the gravel exit port 110 toreturn pressure integrity to the assembly which includes multiplemodules 100. In sequence and working uphole the zones can be fracturedand gravel packed before selective production can begin from one or morezones at a time, as desired. Optionally, the fluid loss valve 148 can beeliminated if the gravel packing assembly shown schematically as 150 haslines 114 and 130 running with it so that a connection C preferably awet connect can be used to connect to the extension of lines 114 and 130in the module 100 to operate the production valve 112 from its openposition during gravel packing to a closed position before the quickconnect is disconnected for fracturing or gravel packing the next zoneuphole. This is shown schematically as dashed line 152.

Another option with a gravel packing assembly as shown in FIG. 4 is toplace a fiber optic cable 154 against the inside of the screen 102 andhave it connected to the surface during gravel packing to give real timescreen stress data as an indication of the effectiveness of the graveldistribution around the screen 102. Schematically lines 156 and 158 showthe fiber optic cable continuing from opposed ends of the cable 154against the screen 102 and heading back into connection C of the gravelpacking assembly 150.

Those skilled in the art will appreciate that the illustrated equipmentand associated method allow for installation of the production valveswith the screen with the hydraulic lines in place and disposed for quickconnection to the next module or to blank pipe via self aligning quickconnections. Ultimately the production string with the associated linesor cables routed into a wet connection can be run downhole and made upwith setting down weight to mate two parts of a wet connect to eachother and in that way activating the entire completion assembly tooperate production valves as needed and to sense well conditions in realtime. The lines can be used for other purposes such as chemicalinjection adjacent any screen. Optionally the fluid loss valves 148 canbe eliminated if the fracturing and gravel pack assembly has the linesand cables and the ability to connect to the production valve which canbe opened to take returns during the gravel packing and shut if doing afrac job or shut after the particular zone is gravel packed andfractured and the running string assembly 150 is moved to the next zoneor out of the wellbore for the production string that wet connects to atopmost packer.

There is now an ability to go beyond the two zones that were theprevious limit because the drop in valves with shrouds as illustrated inFIG. 2 had a limit because of space requirement for the shroud. Theshrouds are no longer needed using the location of the valve 112 on theblank pipe 104 and preferably offset from the screen to make room forthe hydraulic operator for the valve 112. The number of zones is not anissue as compared to the drop in valve design of FIG. 2. The assemblycan be further simplified by the elimination of the valve 148 and stillhave a fluid loss feature by enabling the gravel pack and fracturingassembly to have lines to engage to operate the production valve 112 fordouble duty. Once for taking returns during gravel packing while beingoperated from the gravel pack assembly and later in production whilebeing operated by the lines associated with the production string thatis wet connected to a topmost packer with all the lines belowpre-connected among the modules and any spacers among them. The gravelpacking assembly can interact with instrumentation on the screen such asa wound fiber optic cable to measure stress on the screen 102 during agravel pack and feed that information during the gravel pack to thesurface through the gravel packing assembly that has with it thecontinuation of the fiber optic line down and back from the screen beinggravel packed. Other parameters can be measured or chemicals injectedthrough the gravel pack assembly when the auxiliary lines are connectedduring the frac or the gravel pack.

The above description is illustrative of the preferred embodiment andmany modifications may be made by those skilled in the art withoutdeparting from the invention whose scope is to be determined from theliteral and equivalent scope of the claims below.

1. An intelligent well completion system for downhole use, comprising: atubular string with at least two screens and at least one packer toseparate the screens into different zones and a gravel port for eachzone; at least a first and a second axially spaced apart valveassemblies respectively associated with said screens, said valveassemblies operable from the surface of the well to selectively allowflow through said screens without intervention in said string.
 2. Thesystem of claim 1, wherein: a plurality of internal pipes each spanninga respective screen internally of said string and further supporting oneof said valve assemblies.
 3. The system of claim 2, wherein: said valveassemblies are actuated from the surface through a control systemextending outside said string.
 4. The system of claim 3, wherein: saidcontrol system further comprises at least one discrete line to eachvalve assembly further comprising at least one quick connection.
 5. Thesystem of claim 4, wherein: at least one said line is a hydraulic linethat extends through said packer.
 6. The system of claim 2, wherein:said string comprises a gravel port valve and a fluid loss valveassociated with each said screen with said fluid loss valve mounted tothe internal pipe associated with a respective screen.
 7. The system ofclaim 6, further comprising: a frac pack assembly further comprising acrossover and a sleeve shifter to selectively operate said gravel portvalve and said fluid loss valve to selectively deliver gravel or fluidthrough said gravel port and to thereafter close off an associatedscreen with said fluid loss valve.
 8. The system of claim 3, furthercomprising: at least one sensor adjacent said screen connected to thesurface through said control system for transmission of data betweensaid screen and said surface in real time.
 9. The system of claim 8,further comprising: said sensor comprises a fiber optic cable mounted tosaid screen to detect strain on said screen.
 10. The system of claim 3,further comprising: said string comprises a gravel port valve associatedwith each said screen; a frac pack assembly further comprising acrossover and a sleeve shifter to selectively operate said gravel portvalve; said valve assemblies are actuated from the surface through afirst control system associated with said frac pack assembly.
 11. Thesystem of claim 3, further comprising: said valve assemblies areadditionally controlled through a second control system that runsoutside said string, thereby allowing a given valve assembly to be usedas a fluid loss valve in conjunction with said frac pack assembly and asa production valve after removal of said frac pack assembly.
 12. Thesystem of claim 11, further comprising: a sensor associated with atleast one said screen to transmit to the surface through at least onesaid control system.
 13. The system of claim 12, further comprising: atleast one said control system further comprises a fiber optic cableextending to said screen or a conduit extending to said screen forchemical injection.
 14. The system of claim 3, further comprising: atleast three interconnected modules in said string, each featuring agravel port, one of said screen spanned by an internal pipe, one of saidvalve assemblies on said internal pipe and a portion of said controlsystem.
 15. The system of claim 14, wherein: at least two modules haveend connections on said control system adapted for quick connection ofsaid control system when said modules are assembled.
 16. The system ofclaim 14, wherein: at least one module has a control system componentcomprising at least one of a fiber optic cable, a sensor for wellconditions, at least one hydraulic line or an open line for chemicalinjection.
 17. The system of claim 14, wherein: at least two moduleshave a seal bore at one end and seal at an opposite end for quickconnection of adjacent modules.
 18. The system of claim 17, wherein:connecting seals on one module into a seal bore of an adjacent modulealso connects portions of said control system at the same time.
 19. Thesystem of claim 18, wherein: the components of said control system thatconnect when modules are pushed together are aligned radially oraxially.
 20. The system of claim 14, wherein: said valve assembliesfurther comprise hydraulically operated sliding sleeves that can beselectively positioned fully open or closed or at least one position inbetween.